使用CSS的计算器布局

<div class="calculator">
  <div class="display">0</div>
  <div class="buttons">
    <div class="button number">7</div>
    <div class="button number">8</div>
    <div class="button number">9</div>
    <div class="button operator">+</div>
    <div class="button number">4</div>
    <div class="button number">5</div>
    <div class="button number">6</div>
    <div class="button operator">-</div>
    <div class="button number">1</div>
    <div class="button number">2</div>
    <div class="button number">3</div>
    <div class="button operator">*</div>
    <div class="button number">0</div>
    <div class="button decimal">.</div>
    <div class="button equal">=</div>
    <div class="button operator">/</div>
  </div>
</div>

.calculator {
  width: 200px;
  border: 1px solid #ccc;
  border-radius: 5px;
  padding: 10px;
  font-family: Arial, sans-serif;
}

.display {
  background-color: #f5f5f5;
  height: 40px;
  line-height: 40px;
  text-align: right;
  padding: 5px;
  margin-bottom: 10px;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-gap: 5px;
}

.button {
  background-color: #e0e0e0;
  border: 1px solid #ccc;
  border-radius: 3px;
  height: 40px;
  line-height: 40px;
  text-align: center;
  cursor: pointer;
}

.button:hover {
  background-color: #d0d0d0;
}

.number {
  grid-column: span 2;
}

.operator {
  background-color: #f0f0f0;
}

.decimal, .equal {
  width: 40px;
}